Conceptual data modeling: entities, properties and relationships
Conceptually speaking, the data model is a structured view of your data founded on
entities, properties (or attributes) and relationships.
Entities are objects described in the database by means of properties. An entity
could be a person, an object, a document or any item we want to record data about.
In the human rights field, we normally describe victims, HR violation events, laws,
acts, courts, etc. This notion is similar to the idea of unit of analysis in social
research methodology.
Properties are descriptive attributes that are assigned to entities. There are various
types of properties, such as text, numeric, select one from a list, select multiple from
a list, date, time, etc. For instance, a victim (entity) is described through a name
(text), an age (number), a date of birth (date), etc. This notion is familiar and could
be articulated to the concept of variable, in statistics.
Relationships allow entities to be connected to each other. They define how entities
interact. For example, one act can have various victims, one perpetrator can be
involved in various acts, etc. Relationships are very important in the data model
since they bring the data structure “to life”. By this expression we mean: to support
dynamic escenarios and flows, avoid or reduce data duplication, to circunscribe
certain properties to a specific context (since out of that context certain data could
generate confusions or mistakes).
In the next section, we provide simple visualizations of data models, based in real cases.
Since the data model could get as complex as the image below, we decided to illustrate
them in a more pedagogical way, if easier we could think of these approximations as
standard formats.
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